Antipsychotics gastrointestinal effects

Contraindications for antipsychotic therapy are few they may include Parkinson s disease, hepatic failure, hypotension, bone marrow depression, or use of CNS depressants. Overdoses of antipsychotics are rarely fatal, except for thioridazine, which is associated with major ventricular arrhythmias, cardiac conduction block, and sudden death. For other agents gastric lavage should be attempted even if several hours have elapsed since the drug was taken, because gastrointestinal motility is decreased and the tablets may still be in the stomach. Moreover, activated charcoal effectively binds most of these drugs and can be followed by a saline cathartic. The hypotension often responds to fluid replacement or pressor agents such as norepinephrine. 

In addition, there are several drugs that are related to the antipsychotics that may also be prescribed to youths for other conditions. These include the antidepressant amoxapine and the preanesthetic droperidol. Metoclopramide and prochlorperazine are related agents that are marketed for their effects on the gastrointestinal system. 

Use of St. John s Wort is complicated by the lack of standardisation of the ingredients. Those who wish to take St. John s Wort should be made aware that it may cause dry mouth, dizziness, sedation, gastrointestinal disturbance and confusion. Importantly also, it induces hepatic P450 errzymes (CYP 1A2 and CYP 3A4) with the result that the plasma concentration and therapeutic efficacy of warfarin, oral contraceptives, some anticonvulsants, antipsychotics and HTV protease/reverse transcriptase inhibitors are reduced. Concomitant use of tr5 to-phan and St John s Wort may cause serotonergic effects including nausea and agitation. 

Answer C. Ocular toxicity is characteristic of chloroquine and hydroxychloroquine. Corneal deposits are reversible, but retinal pigmentation can ultimately lead to blindness. Patients will complain about gastrointestinal distress, visual dysfunction, ringing in the ears (note that tinnitus also occurs in salicylism), and itchy skin. Hydroxychloroquine also promotes oxidative stress that can lead to hemolysis in G6PD deficiency. DMARDs include gold salts (e.g., auranofin), methotrexate, and etanercept, but thioridazine is a phenothiazine used as an antipsychotic it lacks an antiinflammatory effect, but does cause retinal pigmentation. 

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